For controlled release of a pesticide active agent, microencapsulation of the agent is widely known. Moreover, in addition to the controlled release of a pesticide active agent, it is also known to achieve its storage stabilization in microcapsules. For example, Patent Literature 1 describes a storage-stable microcapsule suspension wherein a hydrolysis-sensitive plant treatment agent is covered with a film by coacervation using gelatin and an anionic polymer such as gum arabic and the film is pre-cured with a tanning agent and further cured using a carbonyl compound. It is described that the microcapsules subjected to such treatments achieve both of storage stability and controlled release. Furthermore, Patent Literature 2 describes that highly practical microcapsules, for example, having a thick and strong wall, can be provided by adding a synthetic polymer as a third component since an accumulating quantity of a capsule wall is small and the wall has porous nature in the case where capsulation is performed by causing complex coacervation using only two kinds of wall materials of gelatin and gum arabic.
On the other hand, it has been attempted to prepare a stabilized formulation of a pesticide active agent that is susceptible to hydrolysis, particularly an aqueous formulation whose needs are high in market. For example, Patent Literature 3 describes an aqueous suspended herbicidal composition containing (1) herbicidal sulfonylurea-based compound, (2) an inorganic salt, (3) at least one sulfonate selected from the group consisting of arylsulfonate, alkylarylsulfonate, and their formalin condensates, and (4) water.